It is not difficult to foresee the evolution of self-organizing wireless networks that are formed from thousands, perhaps millions, of small sensors. The network can be ad hoc in nature resulting from the deployment of sensors in a random or pseudo-random manner. The sensors must then communicate with one another in order to organize themselves into a network so that they may implement their intended functions.
Such networks are attractive because they provide solutions in many applications such as wireless communication, remote monitoring, surveillance, etc. Applications involving wireless networks are particularly attractive where using wiring to interconnect nodes is difficult, or impossible, or too expensive, or where operating and supporting costs are prohibitively high.
Security in wireless sensor networks is important because many applications are dependent on the secure operation of the sensor networks, and have serious consequences if the network is compromised or disrupted by an attacker. For example, an attacker can modify messages and/or inject fresh messages into the network that subvert the operation of the network. The attacker can also impersonate a particular node in a network in order to intercept messages from other nodes.
For a secure design of a wireless sensor network, it is important to be able to encrypt and authenticate messages sent between sensor nodes in order to prevent attacks, such as impersonation attacks, eavesdropping attacks, honest verification attacks, etc. However, before messages can be encrypted and authenticated, keys for performing encryption and authentication must be agreed upon by the sensor nodes. Due to resource constraints, however, achieving key agreement in wireless sensor networks is a non-trivial matter.
Key pre-distribution schemes have been proposed that substantially improve the resilience and security of the network and associated overhead. These schemes rely on probabilistic key sharing among the nodes of a random network graph and use simple protocols for shared-key discovery and path-key establishment.
In addition, as discussed below, the securing of a wireless sensor network can be improved by the proper design of the network.